Dynamoelectric machine



Oct. 31, 1944.

G, P. DAIGER Erm. 2,361,748

JYNAMO ELECTRIC MACHINE Filed Dec. 15, 1941 2 Sheets-Sheet 1 y M? TTORNEYv OC- 31, 1944- G, P. DAIGER r-:TAL

DYNAMO ELECTRIC MAGHNE Filed Dec. l5, 1941 2 SheetswSheei 2 PatentedOct. 31, 1944 DYNAMOELECTRIC MACHINE George P. Daiger, Canton, andWilliam H. Kitto,

Greentown,

Ohio, assignors to The Hoover Company, North Canton, Ohio, acorporation` of Ohio Application December 15, 1941, Serial No. 423,006

1 Claim.

The present invention relates to suction cleaners and more particularlyto electric motors therefor.

An object of the invention is to provide a new and improved suctioncleaner. Another object is to provide a new and improved motor forsuction cleaners. A further object is to provide armature and fieldcores molded from a. compound of small particles or pulverized magneticmaterial mixed with an insulating binder such as a synthetic resin.Another object is to form the motor cores by sintering the magneticparticles with a cement to bind the particles together. A further objectis to provide molded field and armature cores having skewed opposingsurfaces for adjusting the air gaps therebetween. Another object is toprovide skewed winding slots on the armature core. Another object is toprovide a molded armature core having rounded corners at the ends of thewinding slots for insulating the latter by dipping the armature core inan insulation, such as cellulose acetate, prior to winding the core.Another object is to provide a molded field core having pre-formed polepieces and pre- Wound field coils. Other objects and advantages ci' theinvention will be apparent from the following specication and drawings,wherein:

Figure l is a side elevation, partly in section, of a motor embodied ina suction cleaner;

Figure 2 is a vertical section, partly in elevation, showing the skewediield and armature cores, and

Figure 3 is a disassembled perspective view of the iield and armaturecores.

Referring to .Figures l to 3, the embodiment of the invention thereindisclosed comprises a suction cleaner having a, casing I provided with adownwardly open nozzle II, connected to a suction air passageway I2communicating with a fan chamber I3 connected to an exhaust passagewayI4 for discharging dirt-laden air into a filter bag I5 removablyattached to the casing I0. The casing I0 is supported on wheels I6 andis propelled over the surface being cleaned by a handie I1 plvotallymounted on the casing, the handle I 1 supporting the upper end of thebag I5.

A motor housing 20 is mounted on the cleaner casing Ill and includeslower and upper housing sections 2I and 22, respectively, formed from aninsulating plastic such as Bakelite. The lower housing section 2lcomprises a bottom wall 23 which forms the top wall of the fan chamberI3 and supports a lower bearing 24 for a motor I8. The upper housingsection 22 is supported on the vertical annular wall 25 extendingupwardly from the bottom wall 23 of the housing section 2 I, and

the top wall y26 of the upper housing section 22 has an opening 21, theperipheral wall of which is spaced from the motor commutator 28. The upper end of the armature shaft 29 is supported in a top bearing 30mounted on a plate 3l supported on an upstanding wall 32 of the housingsection 22, the latter and the plate 3l forming a motor Ventilating fanchamber 33 having a ian 34 mounted on the armature shaft 29. The motorI8 drives a fan 35 and a pulley 36 the latter being connected by meansof a belt 31 to a surface agitating member 38 rotatably mounted in thenozzle Il. Enclosing the motor housing 20 is a casing 39 supported onthe cleaner casing I0 and is provided with a transparent window 40through which light raysfare transmitted from an electric lamp 4Imounted on the motor housing 20.

The motor I8 is cooled bymeans of the fan 34 which draws air through anopening 42 in the lower casing section 2l and thence over a field core43 into the fan chamber 33, the air being expelled over the lamp 4I andthrough an unshown opening in the housing 20.

The motor I8 is of the unicoil type and includes an armature 45 and asubstantially U-shaped field core 46. The field core 46 is molded in twocomplementary sections 41 and 48. Each section is molded from a compoundincluding small particles or pulverized magnetic metal such as iron, oran alloy, the particles being insulatably bonded together by means of aninsulating binder as, for example, a synthetic resin. Each core sectionis molded to provide a pole face 49 between pole tips 50, 5I and thepole faces are skewed at an angle to the longitudinal axis of thearmature shaft 29. The skewed pole faces 49 are of greater width thanthe remaining body portion 52 of the core sections 41 and 48. The coresection 41 is molded to form a cylindrical bobbin support section 53having a bore 54 therethrough and an unshown enlarged bore section atits end 55 in which is a diametrically arranged key slot 55. The othercore Asection 48 is also molded with a bobbin support section 51 and aprojecting pilot 58 of reduced diameter, and arranged on the latter is akey 59. A bore extends through the projection 58 and the bobbin supportsection 51.

The molded core sections 41 and 48 are assembled by inserting the pilot58 into the unshown enlarged recess in the bobbin support section 53 andare placed in proper alignment by fitting the key 59 into the slot 5B. Abolt 6I extends through the openings 54 and 60 to rigidly Secure thecore sections together. Prior to assembling the core sections, a bobbin62 of insulating material and pre-wound with the field coil 43 is placedon the bobbin support section 53, and when the core sections areassembled the flanges 63 of the bobbin abut the shoulders 64 at theinner ends of the bobbin support sections 53 and 51 to position thefield coil with respect to the armature 45. The assembled field core issupported in the motor housing section 2| by means of bolts 65 extendingthrough the molded field core and fastened to the bottom wall 23 of thehousing section 2|.

The armature 45 comprises a core 66 molded from a compound includingsmall or pulverized particles of magnetic material, the particles beinginsulatably bonded together by an insulating binder as, for example, asynthetic resin. The

peripheral surface 61 of the core is in the shape' of a frustum of acone and is provided with molded Winding slots 88 which are disposed atan angle with the longitudinal axis of the armature shaft. A winding 09is arranged about the molded core 65 and is connected to the commutator28.

If desired the peripheral surface of the armature core and the polefaces may be molded for arrangement parallel to the armature shaft andnot skewed at an angle as shown in Figures 1 to 3.

In molding the armature core 6B, the opposite end corners 10 of thewinding slots 6B are rounded whereby the core may be, for example,dipped in an insulating varnish or cellulose acetate and the armaturefield may then be Wound directly thereon. Rounding the end corners ofthe winding slots prevents the insulating varnish from breaking at thecorners to thereby provide a completely insulated armature core for thewinding 89. The longitudinal walls of the winding slots 68 are molded toprovide a smooth surface so that the insulating varnish completelycovers the walls of the slots I5.

In assembling the armature and the field core, the conical surface i1 ofthe amature core Il is placed between the inclined pole faces I9 of thefleld core and the air gap therebetween is adjusted by moving the fieldcore and armature with respect to each other. It will be noted that thepole faces 49 are of greater width than the peripheral surface 8l of thearmature core to provide for varying the air gap therebetween withconsequent improvement in the flux distribution between the armature andthe field.

The eddy current losses -are greatly reduced since the opposing surfacesof the pole faces I! and the peripheral surface 51 of the armature core66 do not present solid surfaces of magnetic material. In providing themolded opposing surfaces 49 and Il, the particles of magnetic materialare insulated from each other to prevent the formation of continuouselectrical paths along these surfaces to thereby reduce eddy currentlosses.

We claim:

An armature for a dynamo-electric machine, comprising a core and itswinding, said core having winding slots extending inwardly from theperipheral surface of the core. a coating of insulation material aboutsaid core and lining said winding slots, said core being composed ofmagnetic particles and an insulating binder molded together to form saidwinding slots and their opposite end corners rounded in a gradual curveextending longitudinally of said winding slots from the opposite ends ofsaid winding slots to the end faces of said core, said molded curvedsurfaces providing surfaces to which said insulation will adhere withoutcracking.

GEORGE P. DAIGER. WILLIAM H. KITTO.

